Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
  • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
  • H02P21/06—Rotor flux based control involving the use of rotor position or rotor speed sensors

Definitions

• the present invention relates to a magnetic flux calculation method used for performing vector control by detecting a torque current component from a voltage and a current of an induction motor.
• a secondary induced voltage obtained by subtracting the impedance voltage of the motor from the terminal voltage of the induction motor is obtained, and the excitation current command is obtained.
• a voltage obtained by adding a voltage corresponding to the excitation command current calculated from the above is derived, and the derived voltage is integrated by first-order lag integration to calculate the magnetic flux.
• the present invention reexamines the characteristics of the magnetic flux calculation value based on the evaluation of the torque current feedback type and the flux orientation type vector control applied in the vector control.
• the purpose is to reduce the increase in phase error.
• the method for detecting magnetic flux of an induction motor of the present invention provides a primary current to be supplied to the induction motor in accordance with an excitation current command value and a torque current command value.
• a vector control device that controls a frequency based on a magnetic flux calculated from a voltage and a current of a motor, When calculating the magnetic flux from the voltage, current and magnetic flux command signal of the induction motor using the primary delay circuit, the time constant of the primary delay circuit is set to be equal to the secondary circuit time constant of the induction motor.
• FIG. 1 is a block diagram showing an embodiment of the present invention
• FIG. 2 is a block diagram showing an example of a magnetic flux calculation circuit
• FIG. 3 is a vector diagram of a secondary magnetic flux.
• the primary current i can be directly detected, and the magnetic flux needs to have a good phase characteristic of 0' ⁇ [that is, a unit vector.
• the improvement of the characteristics of the arithmetic magnetic flux vector was studied at a low frequency where the arithmetic error increases, and the phase error was reduced particularly in the motor constrained state.
• Figure 2 shows a block diagram of the magnetic flux calculation circuit.
• 31 is an inverter.
• 42 is an induction motor.
• the current of the induction motor 42 is detected by the current detector 32.
• the voltage is detected by the voltage detector 33.
• 34, 35, and 38 are constant units, 36 and 4] are subtractors, 37 and 39 are adders, and 40 is a primary delay circuit.
• the secondary flux linkage ⁇ 2 is calculated by the following equation. one-
• p is a differential operator
• Tc Time constant of first-order lag ⁇ 2 *: Magnetic flux command (vector amount)
• Fig. 3 shows a vector diagram of the secondary magnetic flux calculated by equation (2).
• the primary current in Eq. (2) can be expressed as Eq. (4) by the excitation current and the torque current, and the excitation current and torque
• the relationship between the currents can be expressed by equation (5).
• T a Motor secondary circuit time constant.
• ⁇ 2 (re) ⁇ 2 [1 + — ⁇ + ⁇ , Tc ——)
• ⁇ 2 (im) ⁇ 2 [-(AR, () ⁇ - ⁇ , T C )
• FIG. 1 is a block diagram showing a configuration example for implementing the magnetic flux calculation method of the present invention.
• 11 is a power supply
• 12 is an inverter
• 13 is an induction motor
• 14 is a current detector
• 15 is a voltage detector.
• excitation current command value ⁇ ⁇ ⁇ and the torque current command value I which are calculated by multiplying the set magnetic flux command value ⁇ 2 * by the 1 ZM constant unit 1 •
• the vector calculator 2 calculates the equations (15) and ⁇ and calculates the primary current command.
• the multiplier 9 sets the primary current command output from the adder 8 to a phase ⁇ 9 and one. Multiplies the primary current command value I, and outputs the primary current command vector i.
• the current controller 10 controls the inverter 12 in accordance with the deviation between the primary current command vector i and the primary current detected via the current detector 14.
• the electric current is being supplied to the electric motor in the same manner as the electric motor.
• frequency controller 5 is torque current command value I and the torque current calculation value ⁇ t. And outputs the frequency ⁇ ⁇ according to the deviation from.
• the integrator 7 calculates the sum of the frequency ⁇ ⁇ output from the adder 6 and the slip frequency command value calculated by using the divider 3 and the constant unit 4, that is, the magnetic flux frequency ⁇ . It integrates and outputs the phase ⁇ of the magnetic flux command. •
• the adder / subtracters 18 and 19 output the motor terminal voltages detected by the voltage detector 15,
• the primary delay circuit 23 is a magnetic flux command vector 0 output from the multiplier 21.
• the secondary magnetic flux ⁇ 2 and the primary current i are calculated by the vector product 25, the amplitude calculator 26, Calculate the torque current it from the divider 27 by the operation of the expression (1).
• the internal induced voltage and the magnetic flux control command which are obtained by subtracting the primary resistance drop and the leakage reactance drop from the terminal voltage of the motor, are combined, and the output of the motor is output.
• the present invention can be used in fields requiring good torque control characteristics over a wide range of speeds, such as tension control and output control, such as paper, film, and metal fibers.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Ac Motors In General (AREA)
• Tests Of Circuit Breakers, Generators, And Electric Motors (AREA)
• Measuring Magnetic Variables (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=13493223

Family Applications (1)

Country Status (8)

Families Citing this family (6)

Citations (2)

Family Cites Families (11)

• 1988
  • 1988-03-26 JP JP7257288A patent/JP2646633B2/ja not_active Expired - Fee Related
• 1989
  • 1989-03-20 WO PCT/JP1989/000296 patent/WO1989009512A1/ja active Application Filing
  • 1989-03-20 US US07/445,675 patent/US5150029A/en not_active Expired - Fee Related
  • 1989-03-23 DE DE68918620T patent/DE68918620T2/de not_active Expired - Fee Related
  • 1989-03-23 EP EP89105271A patent/EP0335269B1/en not_active Expired - Lifetime
  • 1989-03-28 CA CA000594882A patent/CA1319949C/en not_active Expired - Fee Related
  • 1989-11-14 KR KR1019890702119A patent/KR950010345B1/ko not_active IP Right Cessation
  • 1989-11-24 FI FI895637A patent/FI895637A0/fi not_active Application Discontinuation

Patent Citations (2)

Also Published As

Similar Documents

Legal Events